As a result of economic activities, combustible materials containing water or moisture are discharged in various forms such as sludge, animal and/or plant wastes, and others. Such combustible materials are subjected to incineration treatment, drying treatment, and others to reduce the volume or weight thereof and then disposed by landfill. Recently, there is an increasing demand to recycle those combustible materials as resources.
As one example of recycling the combustible material, a biomass fuel made from combustible material is disclosed in Patent Document 1. This document teaches the biomass fuel prepared in such a way that the surface of biomass granulated material having a reduced moisture content percentage is coated with a deodorant coating layer. This is intended to reduce odor or smell peculiar to organic wastes which are raw materials of the biomass granulated material and thereby improve the ease in handling the biomass fuel.